Balanced let-off for looms



May 10,1927. KJ. UNWIN I 1,527,813

BALANCED LET-OFF FOR LOOKS Filed Oct. 17; 1 925 mm; 110m Patented May 10, 1927.

barren STATES PATENT OFFICE.

KENNETH J. UNWIN, OF WORCESTER, llIASlACHU21 K171S. ASSIGNOR TO GROMPTON & KNOWLES LOOM \VORKS, OF. WORCESTER. MASSACHUSETTS, A. CORPORATION OF' MASSACHUSETTS.

BALANCED LET-OFF FOR LOOMS.

Application filed October 17, 1925. Serial No. 63,176.

This invention relates to lef-ofi" motions for looms and it is the general object of the invention to provide a let-off suitable for heavy looms where the warp can be turned back at the time of pick-out without reversing the warp drum and'wherein the warp will be placed under the same tension immediately after the pick-out as existed be fore the pick-out.

In co-pending application Serial No. .63,- 177 there is shown a pair' of devices both capable of exerting the same tension on the warp threads one of which isnormally operative and the other normally idle. At the time of pick-out the normally operative device is held against movement and the nor mally idle device is releasedto move down wardly and take up the thread turned back after the pick-out. In said application an auxiliary friction pad is applied to the normally operative device and in co-pending application Serial No. 63,175 this auxiliary pad is disposed of, the extra friction being applied by raisingthe control lever usual in the type of loom to which my invention more particularly relates. In this latter application it is necessary to give each of two' control levers separate movement.

It is another object of my invention to improve upon the construction of the latter application to the end that a single hand lever may be employed to render the normally idle device operative and at the same time to raise the control lever for placing additional friction on the normally operative drum.

It is a still further object of my invention to provide the usual friction control lever, screw and block with a single lever pivoted on the block and so placed as to engage the control lever in all adjusted posi tions thereof.

With these and other objects in view which will appear as the description proceeds, my invention resides inthe combination and arrangement of parts hereinafter described and set forth in the claims.

In the accompanying drawings wherein I have shown a convenient embodiment of my invention, I

Fig. 1 isa side elevation of a loom having my invention applied thereto and showing the same under normal weaving conditions,

Fig. 2 is a view similar to Fig. 1 but showing the parts moved to the'position they assume after a pick-out and before weaving 1S resumed,

Fig. 3 is a horizontal section on line 3-3 of Fig. 2,

xFig. 4-

an enlargedfragmentary View looping in the direction of arrow 4, Fig. 1, ant

Fig. 5 is a side elevation taken in the direction of arrow 5, Fig. 4, but showing the parts in position for a pick-out.

' Refr rrring to the drawings it will be seen thatI have provided a loom frame having pivotally mounted at the rear thereof a warp drum 11 the opposite ends of which are provided with friction heads 12 only one of which is shown in the drawings, see Fig. I. friction strap 13 anchored at fixed point 14 on the loom is provided for each friction head and is connected by means of a link 15 to a lever 16 secured to shaft 17 extending across the loom. Adjustable link 18connects one of the arms 16 and leg 19 of the control lever 20 which is pivoted at 21. Control lever 20 extends forwardly and normally rests on a. block 22 the rear face of which engages the upright portion of a stand 23 secured to the loom frame. A screw 24 extends through the block and a pair of spaced arms 25 on the stand 23 and is controllable by a hand wheel 26, upward displacement of the screw being prevented by collar 27 secured to the screw and engaging the under side of upper arm 25. The matter thus far described is of very common construction in duck looms and has been used for many years, theturning of the screw either raising or lowering the control lever to increase or diminish the friction between the bands 13 and the heads 12.

I provide a frame 28 pivoted as at 29 to the loom and having each side thereof provided with adjustable weights W and a looking tooth 30. A pair of latch levers 31 are secured to a cross shaft 32 journa-led in a rear bracket and each of said latch levers is provided with a notch 34 proportioned to receive a locking tooth when said latch levers are forward and the frame 28 is raised as shown in Fig. 1. Secured to and depending from the cross shaft 32 is an arm 35 the lower end of which is attached to a connector 36 having flexible portions to extend around sheaves 87 and 38, respectively,

said flexible connector extending toward the frontof the loom. A weighted roll 39 is rotatably mounted in frame 28 so that the warp threads T after passing around the friction drun'r 11 pass over guide bar :0, under the roll 3'9, and over a second guide bar 41 torwardly to the weaving instrumentalities. Each latch lever 31 is held yieldingly in forward position by a spring 42 and springs 43 may be connected to the levers 16 to hold the control lever 20 seated on block 22.

My improvements relate more particularly to means for actuating the connector 36 and raising the control lever 20 to increase the "Friction on the drum 11. In carrying out my invention 1 provide the block 22 with a stub shaft 50 loosely mounted therein for free rotation and secure to one end of said shaft a finger 51 which lies under a shelf 52 termed on the control lever 20. The control lever projects below the shelf to form a decent which will engage the projection 22 on block 22 and also finger 51 to prevent accidental unscating ot'. the control lever. The other end of the stub shaft 50 has secured thereto a hand lever 53 the upper end of which is attached to the connector 36.

It is to he understood that each oi. th warp tensioning devices described, namely, the drum 11 and the roll 39, capable of exerting the same tension on the warp threads but that under normal conditions the roll is held in locked position as shown in Fig. 1, tension on the threads icing exerted by the drum 11. At the time of a picleout the detective picks are removed and this will leave a stretch of warp lying between the reed line and the new fell. In order to move the new fell back to the reed line the operator will. depress lever 53 which has simultaneous action on both tensioning devices, swinging the latch levers 31 to unlock roll 39 and at the same time raising control lever 20 slightly. This results in an increase in tension of the "friction bands 13 so that the drum now exerts more tension on the "(1'13 threads than is exerted by roll 39. eaving is resumed and as it continues the roll 39 will be raised until it is in normal position at which time the weaver will. release lever and return the same to normal position. This will permit springs 42 to cause locking eng gement between the latch levers and the frame 28 and will also restore normal tension on the friction bands 13. In this way I am enabled to control Si. multaneously both devices rendering one operative and the other inoperative at will by the n'ianipulation oi the single device.

In Fig. 2 the linger 51 is shown oblique with respect to a vertical line and it is to he understood that this condition exists when the piclz-out is very short. It the pick-out be of any length so that the weaver might desire to be free for other duties during the taking up of the reversed warp the hand lever 53 may be turned to the position shown in 5 where the broad fiat upper surface of the linger 51 rests against the bottom ot shelf 52 to serve as a lock to hold the parts as shown in d Fig. 5. In this position the contact between the finger and the shelf ex tends on both sides of a line drawn through the stub shaft 50 and perpendicular to the shelf.

From the foregoing it will be seen that I have provided a convenient means for simultaneously controlling a pair of warp ten-v sioning devices by operating upon the usual control lever and that said means is operative in any adjusted position of the block 22.

Having thus described my invention it will be apparent that changes and modifications may be made therein by those skilled in the art without departing from the spirit and scope of the invention, and I do not wish to be l iuitml to the details herein disclosed but what I claim is:

l. In a let-elf mechanism for a loom having a pair of alternately operative devices each capable when operative of exerting the same tension on the warp, means to hold one of said devices normally inoperative to tension the warp, means normally acting to cause the other device to exert tension on the warp, an element connected to the last named means effective to cause said last named means to exert a predetermined tension on the warp, said element being movable to increase the tension exerted by said other device, and a member to move the element to increase the tension exerted by said other device to prevent the latter from delivering warp and operatively connected to the lirst named means to render operative the device normally inoperative to tension the warp.

2. In a let-oil mechanism for a loom having a pair of alternately operative warp tensioning devices each etlective when operative to exert the same tension on the warp and one of which is normally inoperative, means including a control lever to exert a predetermined tension on one oi said devices, the control lever being movable to increase the tension exerted by the device associated therewith, locking means to hold the normally inoperative device out of action, and a member common to the locking means and the control lever to move the latter to increase the tension exerted by the device associated with said control lever and to release the device normally held inoperative by the locking means.

3. In a let-ofi" mechanism for a loom having a pair of alternately operative devices each capable when operative of exerting the same tension on the warp, means to hold one of said devices normally inoperative, means to cause the other of said devices to exert tension on the warp, said latter means including an element operative at all times to control the tension exerted by the other device, said element being movable to increase the tension exerted by said other device, and a member operatively connected to the normally inoperative device to render the latter operative and at the same time to move the element to increase the tension exerted by said other device.

4. In a let-oif mechanisn'i for a loom having a pair of alternately operative warp tensioning devices each effective when operative to exert the same tension on the ,warp and one of which is normally inoperative and the other of which is normally operative, friction means to vary the tension exerted by the normally operative device, a movable block operatively connected to the friction means, and a member carried by said block and effective to have operative contact with the friction means to increase the tension' exerted by the normally operative device, said member being ettective also to render the normally inoperative device operative.

5. In a let-ofl inechanisml or a loom having a pair of alternately operative warp tensioning devices each effective when operative to exert the same tension on the warp, one of said devices being normally inoperative and the other normally operative, a rotatable screw, a block mounted on the screw and movable. therealong as the screw is 1'0- tated, friction means for one of said devices including a control lever normally resting on the block, a lever pivoted on the block and effective in all adjusted positions thereof to move the control lever to increase the friction of the associated device, and connections between the member and the other of said devices to render said other device operative when said member increases the friction of the first named device.

6. In a let-off mechanism for a loom having a pair of alternately operative warp tensioning devices each effective when 01)- erative to exert the same tension on the warp,

:triction means associated with one of said devices to exert tension on the warp including a control lever, an adjustable support for said lever to vary the tension exerted on the warp by the device associated therewith, lockingmeans to hold the other of said devices normally inoperative, and a member n'iova-bl'e with said sup portingmeans to simultaneously act upon the control lever to increase the tension exerted on the warp by the device associated therewith and also move the locking device to unlocking posi tion to render the other of said devices opera-live.

7. In a let-oft mechanism for a loom having a pair of alternately operative warp tensioning devices each effective when operative to exert the same tension 011 the warp, friction means to cause one of said devices to exert tension on the warp, a. control lever operatively connected to said friction means,

a movable support for said lever, locking means to hold the other of said devices normally inoperative, a hand lever pivotally mounted on the movable support, connections between said hand lever and the look ing devices, said hand lever being movable in all adjusted positions of the movable support to act on the control lever to increase the warp tension exerted by the associated device and to release the locking means to render the other of said devices operative.

8. In a device to exert temporarily increased tension on the warp of a loom, a warp delivery means, a friction device to retard said means, a control lever operatively connected to the friction device, a movable support for said control lever, and an auxiliary lever pivoted on the movable support and effective to temporarily move the control lever to increase the tension exerted by the liriction device, said auxiliary lever being returnable to normal position to restore the original tension.

In testimony whereof I have hereunto atfixed my signature.

KENNETH J. UNWIN. 

